1. Field of the Invention
This invention relates to compositions and processes for non-permanently coloring keratinous fibers, particularly hair on the human scalp, comprising the use of sulfo-containing, water-dispersible, colored polymers wherein the colorant moiety is incorporated into or onto a carbonyloxy and/or carbonylamide backbone of the polymer. The polymers are uniquely designed to offer cosmetically desirable color coatings on hair and to be easily dispersible in hot water, yet offer excellent resistance to redispersion in water at room temperature.
2. Description of the Prior Art
It is very desirable to offer users of hair colorants the option of coloring their hair in such a manner that the effect of the coloring treatment can be easily removed or reversed by the use of regular, commercial shampoo products. Uncertainty and concern about selecting the right color, the wish to easily experiment with different hair tonalities, and the changing requirements of fashion and lifestyles, all contribute to the desirability of non-permanent hair coloring products. Additionally, there is a frequent need to modulate or adjust the color produced by prior, more permanent color treatments. This is especially desirable in order to compensate for the gradual color fading which is always observed after using even the most permanent hair coloring products.
Another application for hair coloring materials which can easily and reversibly color hair comprises incorporating them into frequently used hair care products such as conditioners, mousses and setting lotions. This allows the user to conveniently tone or introduce color highlights in the hair without the need for a separate coloring process.
Customarily, hair is colored using low molecular weight compounds which penetrate the keratinous fibers. This approach has been successful for producing permanent and semipermanent color effects on hair. It requires, however, some affinity between the chromophore-bearing molecules of the colorant and the fibers and, as a result, it becomes very difficult even after repeated shampooing to remove all the colorant which has penetrated into the hair. In addition, these permanent and semi-permanent treatments are very sensitive to variations in the quality of hair among different individuals. Treatments which do not penetrate the hair fibers, but which color hair by depositing colored materials only on the hair fiber surface, are practically insensitive to such variations, can be easily removed and have therefore been proposed and used for the non-permanent, i.e. totally reversible, coloring of hair.
U.S. Pat. No. 4,559,057 describes the use of insoluble pigments. Due to their poor adherence to the hair surface, they are to be used together with a polymeric binder in order to reduce rub-off of the color and produce acceptable color coatings on hair. Insoluble pigments are very different from the soluble dyes of the present invention.
U.S. Pat. No. 4,804,719 discloses polymeric compositions which contain carbonyloxy and carbonylamide links, particularly polyesters and polyesteramides, having water solubilizing sulfonate groups and colorants, copolymerized onto or into the polymer backbone. It is indicated in this patent that these polymers are useful in adhesives, coating materials, films and packaging materials. It is also stated therein that aqueous dispersions of these materials have utility as inks, paints and other industrial coatings, all of which are intended to be permanent in nature. No disclosure is made relating to the specific art of dyeing keratinous fibers, non-permanently or otherwise.
Various examples of thermally stable industrial colorants useful for manufacturing colored polymers through incorporation into or onto the sulfopolyester polymer are described in U.S. Pat. Nos. 2,571,319; 3,034,920; 3,104,233; 3,372,138; 3,417,048; 3,489,713; 3,278,486; 3,359,230; 3,401,192; 3,417,048; 3,424,708; 4,049,376; 4,080,355; 4,088,650; 4,116,923; 4,141,881; 4,202,814; 4,231,918; 4,267,306; 4,279,802; 4,292,232; 4,344,767; 4,359,570; 4,403,092; 4,477,635; 4,594,400; 4,617,373; 4,617,374; 4,740,581; 4,745,173; 4,808,677; 4,892,922; 4,892,923; 4,958,043; 4,999,418; 5,030,708; 5,032,670; 5,075,491; 5,086,161; 5,102,980; 5,106,942; 5,151,516; 5,179,207; 5,194,571; 5,274,072; 5,281,658 and 5,384,377. None of the above references suggest the application of the industrial colorants to human hair.
U.S. Pat. Nos. 4,300,580 and 5,158,762 disclose hair spray compositions comprising colorless, sulfo-containing, water dispersible polyesters which are useful for giving hair a firm texture and for holding hair in a desired arrangement for a certain length of time. These polymers are fundamentally different from those in the present invention in that the reference does not teach or suggest colored molecules. Inherently, they also fail to suggest incorporating colored molecules into or onto the polymeric backbone.
In order for colored polymers to be useful in non-permanent hair coloring they must fulfill a number of requirements which are quite distinct from those necessary for hair spray resins. Specifically, they must form films that strongly adhere to the hair surface. Such films must also remain flexible enough under different temperature and relative humidity conditions so as to withstand the bending of hair without fracturing and separating from the fibers. They should, however, be hard enough to prevent the transfer of color if rubbed against parts of the body, clothing, etc. They must be easily and completely removable by shampooing and yet, in order to prevent color bleed, they cannot be easily redispersed or resolubilized by contact with water at room temperature. They must also obviously be safe and not irritate or stain the skin. In contrast, hair spray and other hair styling colorless polymers are practically invisible to the naked eye. As a result, rub-off onto other surfaces, moderate flaking of fractured film particles, incomplete shampoo removability, and "bleed" upon exposure to water would not be noticed. Unlike the aforementioned colorless polymers, the intense coloration of the polymers described in this invention would make even small-trace quantities of them quite obvious, and easily noticeable on hair, other surfaces and in solution. It can thus be easily understood that the requirements for hair spray or hair styling colorless polymers are intrinsically far less stringent than those for colored polymers for use in non-permanent hair coloring products. It is then by no means anticipated that, if a certain type of colorless polymer useful in hair fixatives could be made colored even without changing its properties, it would then also be advantageously useful for non-permanent hair coloring. It is moreover well known to those familiar with polymer chemistry and properties that it is extremely difficult to incorporate a new and different comonomer into or onto a polymer backbone without substantially changing the properties of the polymer.
U.S. Pat. Nos. 3,251,743 to BASF and 3,535,255; 3,567,678; 3,597,468; 3,617,165; 3,619,101; 3,720,653; 3,763,086; 3,797,994 and 3,915,635 to L'Oreal disclose colored polymers and compositions for coloring hair. These polymers are structurally different from those disclosed in the present invention in that they do not have solubilizing sulfonate groups and they have a hydrocarbon backbone. They rely instead on carboxy groups which in some cases have to be neutralized by organic or inorganic bases in order to make these polymers water soluble. Alternatively, they can be dissolved in alcohol or alcohol-water solutions.
U.S. Pat. No. 4,182,612 describes a new class of water soluble cationic colored polymers useful for dyeing hair prepared by the colorant reaction of chromophores with selected polymer backbones. U.S. Pat. No. 4,228,259 also describes the preparation and use for dyeing hair of water soluble cationic colored polymer having various amine groups wherein said amine groups are either a part of or aid in the linking to the polymer chain of an aryl or arylaliphatic chomophore. The polymers in both of these patents are different from those in the present invention in that they do not have water solubilizing sulfonate groups and the structure of the backbone is very different. In addition, and by design, their cationic nature gives them a very strong affinity for hair, making them very shampoo resistant and therefore not suitable for temporary, i.e. easily removable, hair coloring treatments.
U.S. Pat. Nos. 4,051,138; 4,144,252; and 4,169,203 to Dynapol describe the composition of water soluble colored anionic polymers. These polymers are different from those of the present invention in various important respects. The polymer backbone is a simple hydrocarbon chain whereas the polymers described in this invention contain carbonyloxy and/or carbonylamide moieties in the backbone. Although the polymers in these three patents similarly have water solubilizing sulfonate groups, these polymers were mainly designed to be used as water soluble colorants in foods and beverages and are so readily and quickly water soluble that they would show excessive color bleeding if used to color hair. In addition, they are not good film forming polymers and, because of these characteristics, they are not useful as substantive hair colorants. In contrast, since the sulfo-containing polymers of the present invention are not readily water-soluble, less bleeding is observed. Thus, they are a major improvement over the Dynapol compounds.
In summary, the colored polymers used in this invention have chemical structures different from the colored polymers proposed as hair colorants in the prior art. The combination of the water-solubilizing sulfonate groups, colored monomers, and the structure of the polymer backbone, which may include three to four additional monomers, is unique. Unexpectedly, this type of structure produces colored polymers which are highly resistant to dispersion in ambient temperature water. As a result, when these polymers are present on the hair surface as dry films, color bleed upon exposure to ambient temperature water is insignificant.